Recent drastic increase in the amount of information handled by computers promotes expansion of the scale of data centers hosting host computers and storage systems for processing information. Servers, storage systems, and networks installed in data centers have attained technological progress to reduce management costs on an individual apparatus basis.
For servers, with enhancement of performance in units of apparatus, an architecture implementing a virtualization mechanism in a highly-integrated blade-type apparatus is beginning to be employed to achieve load balancing among a plurality of servers. To storage systems, a design that stores consolidated massive data in a large-scaled storage system with high performance, high reliability, and high availability is applied, instead of storing massive data in a number of small storages. As to network equipment, increasing the number of connections per apparatus improves performance to bear increased traffic among systems.
In such circumstances, data centers come to face a problem of management cost for procuring individual apparatuses and constructing and operating large-scale systems. To reduce the cost, integrated systems including built-up systems with servers, storages, and networks are beginning to be proposed.
Such an integrated system includes built-up components of servers, storage systems, and networks with determined specifications; accordingly, if it is assumed to use it within the range of its specified performance, construction and operation costs can be reduced.
An issue to improve the system performance is management of storage systems. Because of difficulties in designing performance and capacity, and difficulties in building up a storage area network (SAN), a large-scale data center employs an administrator specialized in the storage system; accordingly, simplification is particularly desired and techniques are under development.
One of the techniques to achieve a large-scale storage system is a storage area network. A storage area network connects one or more storage systems to a plurality of host computers so that a plurality of host storages can share a huge capacity storage system. Such computer systems are currently widespread.
An advantage of such a computer system is an outstanding extendability: storage resources and computer resources can be easily added, deleted, or replaced at a later occasion. For a storage system that connects to a SAN, a storage system including RAID (Redundant Array of Independent Disk) structured storage apparatuses are commonly used.
A fibre channel switch included in the SAN provides a zoning function. A zone is a unit of logical separation of a fibre channel network. A scheme of this fibre channel zoning configures a zone with a group of network interfaces.
The network interfaces registered in a zone do not accept data transfer to and from network interfaces which are not registered in the zone. In other words, data transfer is available only among the network interfaces registered in the zone. The fibre channel switch can manage information on equipment connected to the SAN fabric, update the statuses in response to a log-in of new equipment or a log-out, and respond to a query about connection status.
PTL 1 in the citation list below discloses a system that connects a virtual storage system to a different external storage system having storage areas to provide a host computer with a storage area in the different storage system to be used as a virtual storage area in the virtual storage system; the technique is called external storage attatchment technique.
PTL 2 discloses a storage system that transfers information in a logical unit (volume) in a migration source storage system so as to match the settings on a migration destination storage system to set configuration control information.
PTL 3 discloses a technique that assigns a global LDEV number common to a plurality of storage systems in addition to a local LDEV number within a storage system. PTL 4 discloses a thin provisioning technique that prohibits allocation of storage capacity to unwritten data areas to reduce redundancy in the storage capacity.